D.J. Wilkie, Medical Surgical Nursing, University of Illinois at Chicago College of Nursing, Chicago, IL; K. Cain, Research and Statistical Consultant, Office for Nursing Research, University of Washington, Seattle, WA; and E. Myklebust, , Pacific Oncolog

Aim: The subjective nature of pain creates measurement challenges for researchers given that the quantitative meanings of verbal pain intensity descriptors are not universally recognized. The purpose of this study was to statistically characterize 26 commonly used pain intensity descriptors with a visual analogue scale (VAS). Method: Randomly selected, 248 inpatients (48% male, age in yr: 25% <40, 49% 40-59, 26%>60, 87% Caucasian) from a Seattle hospital used a 100 mm VAS to rate the intensity of the descriptors. Each patient completed 36 randomly ordered VASs, 10 of which were replications: two descriptors for all patients and 8 descriptors randomly selected. This design allowed for analysis of presentation order effects and test-retest reliability for each descriptor. We used a highly reliable computerized digitizer tablet to measure all scores. Results: Except for descriptors with medians close to 0 or 100 mm, there was large, across-patient variability for the descriptors. For example means (SD) for descriptors commonly used in verbal rating scales were: no pain 0.7 (2.4); mild 16.2(12.2); discomforting 31.3 (22.2); distressing 55.3 (24); horrible 87.8 (13.6); excruciating 94.6 (9.3). Test-retest reliability indicated small within-person variability on scores assigned to each descriptor. There were some significant but rather small effects of presentation order for 13 descriptors. Conclusions: Findings contribute estimates for the magnitude of pain represented by each of 26 the descriptors. However, the wide variability in patients' perception of word meaning likely will add measurement error when verbal descriptor scales are used as pain outcome in research.